On the F280049PZS, why does applying 3.3V to an analog input result in an ADC reading of approximately 2048 (half scale)? What could be causing this and how can it be correct

Dear all,

I'm using the F28002x/003x/004x ADC block in MATLAB R2025a to read an analog input. Although VREFHI is set to 3.3V, applying a 3.3V input only yields a value of around 2048, which suggests the ADC is operating at 11-bit resolution instead of the expected 12-bit.

Does anyone know how to resolve this issue?

Best regards,

METHEE

Answer 1

[Kautuk Raj]

This issue may occur when working with the F28002x/003x/004x ADC in MATLAB/Simulink, especially if the configuration is not perfectly aligned between the hardware and the model.

Here are some steps and checks to help you resolve this:

• Double-check block resolution setting in Simulink --> Refer to https://www.mathworks.com/help/ti-c2000/ref/model-configuration-parameters-for-texas-instruments-c2000-processors.html
• Confirm VREFHI is truly 3.3V on your hardware --> Refer to https://www.ti.com/lit/pdf/sprui33
• Check your code’s initialization for ADC resolution --> Refer to https://www.mathworks.com/help/ti-c2000/gs/overview-of-creating-models-for-c2000-processors.html